Heparin content of washed red blood cells from the cardiopulmonary bypass circuit.

Reinfusion of red blood cells (RBC) from the extracorporeal circuit following cardiopulmonary bypass (CPB) reduces patient exposure to homologous blood. Because infusing unneutralized heparin might exacerbate postoperative bleeding, this study examines the heparin content of the washed packed RBC produced by a commonly used autotransfusion device. This RBC product was derived from the residual whole blood in the oxygenator circuit after CPB. A wash volume of 750 mL of normal saline produced heparin concentrations below 0.04 USP U/mL. A 500 mL wash volume yielded heparin concentrations ranging from 0.08 to 0.22 USP U/mL, and could be used if time did not permit an additional wash. RBCs produced by the usual complete wash cycle do not contain clinically significant amounts of heparin; thus, they would not require a supplemental protamine dose.